Went to Win7 Pro 64bit from WinXP Pro 32bit and downloaded Designer 5.0 SP6 which installed fine and Builds the Project located in the XP folder without a problem. On shutdown of Designer (but only if I Build a project) I get a " CMX MFC Stopped Working" message.

I would suggest at first glance that you install Designer 5.2. That is running without complains on several of my machines up to win7 64. Is there an absolute need for you to use an outdated Designer version? One of the reasons afaIk might be to keep the HighTech-C-Compiler. Cypress changed to ImageCraft which is a bit different and a bit (rather: BYTE) more code consuming.

Designer download took me to the 5.0, I will look for 5.2. Hope it is available as an update and not a large download.

Found oleaut32.dll is a MisterSoftee dll. There are numerous other dll's that link to it including C++ Runtime Library. Found a post that said to try a "sfc.exe /scannow" but it is happy with what it checked. Will also try a WinMerge compare between this dll if the versions are at least close.

5.2 is a complete new version, co-existent with 5.0 both using ImageCraft C-compiler. Will take some time to download and install. Use download from Cypress's website under Support -> Software Downloads -> PSoC Designer.When it turns out to be a windows-problem I would think about de-installing the older versions at first to get a clean machine.

oleaut32.dll is involved with all of the above (I think), no idea which cured the problem.

I will go to Designer 5.2 when I get the time. Right now it is working fine and my project does not need any further PSoC1 coding revisions. Am working on the PSoC3 portion of the project; PSoC3 chips are much better suited for my needs; if Creator supported RF I would switch completely to PSoC3.